The invention relates to an abrasion-resistant jacket for a flexible cable with a cable core and a jacket made of an abrasion-resistant thermoplastic material surrounding the cable core, particularly for a drag chain cable or a robot cable.
To control modern robotic and handling systems, lines with a high degree of flexibility and fatigue strength under reversed bending stress are required. Such lines are in continuous motion during operation. They must withstand torsion values of ±440° in continuous operation.
The October 2000 issue, volume 82 of the periodical “Elektrotechnik” describes a highly flexible cable for use in modem robots in which several individual cables are accommodated in a hybrid line. The individual cables are unit stranded around a conductive core. To minimize friction of the individual structural elements, these elements have low-friction insulating surfaces and extensive wrapping. Preferred insulation materials are those based on polyurethane, which are distinguished by high abrasion resistance and resistance to hydraulic fluid and mineral oil. Thermoplastic elastomers are used for the jacket, so that the jacket is resistant to notching and abrasion.
In addition to this material, a halogen-free and self-extinguishing polyurethane-based jacket material has become known in the art, which is being used with great success for welding lines because of its high flexibility and extreme protection against weld spatters.
As a result of the significant mechanical loads due to bending, torsion and especially friction which occurs frequently because of tight spaces, abrasion of the jacket is so severe that the cables have to be replaced after a short time. Downtimes are expensive, however, and the operators of assembly lines equipped with robots are very reluctant to accept them.